The present invention is related to a carrier for pipette tips, for those in automatic machines in particular.
Carriers for pipette tips serve for keeping and providing pipette tips made of plastic material for utilisation. They have an edge with four upwardly projecting side walls and a plate, disposed on the upper edge of the frame and having a plurality of holes in a matrix arrangement. Pipette tips are put into the holes from out the upside, wherein they do not fall through the holes due to a diameter that widens towards the upside, or due to a collar. The frame is adapted to be put onto a support with its lower edge or a bottom. The pipette tips are held at a distance from the support by the carrier. One or plural pipette tips may be taken out of the carrier by means of a pipetting—or metering apparatus, respectively. For this purpose, the metering apparatus is pressed into the upper opening of one or plural pipette tips with one or plural studs. After use, the pipette tips are normally put into a carrier or given off into a container with the aid of a throw-off device of the metering apparatus, in order to be disposed of.
Carriers for pipette tips are known wherein the frame is covered by a bottom at the downside, and by a detachable cover cap on the upside. In these box-like carriers, the pipette tips are protected against contaminations. Before taking out pipette tips, the cover cap has to be removed.
From WO 00/51899 A1, the entire contents of which is incorporated herein by reference, a refill package for re-usable carriers for pipette tips is known. The refill package comprises a plate with holes in a matrix arrangement, into which pipette tips are inserted, and a flexible cover cap in which the plate is held. When putting the cover cap onto the upper edge of a carrier, the side walls of the cover cap are laterally deflected, so that the plate clamped in there between is released. As a consequence, the plate with the pipette tips falls into a reception piece of the carrier that is surrounded by an enclosure. Refilling the carrier with pipette tips and taking out the plate with pipette tips from the carrier are performed manually.
In automatic metering machines and automatic laboratory machines (“workstations”) that include metering apparatuses, pipette tips made of plastic material are frequently employed. Automatic metering machines and automatic laboratory machines will be designated as “automatic machines” in the following. The known refill package is not well suited for the utilisation in automatic machines. Displacement of the cover cap by an automatic machine in order to separate plate and cover cap would be problematic due to the cover cap's flexibility. When the plate is disposed in the carrier, the lateral enclosure encumbers the removal by an automatic machine.
From U.S. Pat. No. 6,221,317 B1, the entire contents of which is incorporated herein by reference, a box for pipette tips is known which features a lower part with a bottom and side walls, which end up in support surfaces at the upside. A plurality of locking elements is asymmetrically disposed on the support surfaces. A plurality of inner walls projecting upward from the bottom is adjacent to a plurality of inner accommodations. A plate portion features a first set of holes, into which the locking elements are inserted. Further, it has a second set of holes for the insertion of pipette tips. The locking elements are realised as locking pins, which engage by frictional fit into the first set of holes of the plate. Thus, plate and lower part are detachably fixed to each other by way of the pins and bores. However, detaching the plate from the lower part is only possible by the expenditure of a force that is greater than the weight force of lower part and plate. The user can choose among plates having 96, 348 an 1536 holes for inserting pipette tips. He can fix the selected plate on the lower part by way of the locking pins and the holes. Thereafter, he may insert the pipette tips into the holes and place a cover cap over the plate.
The grid-like subdivision of the interior space provides the box with a stiffness sufficient for handling by an automatic machine. Automatic refilling of pipette tips into the box would be a problem. In particular, replacing a plate by a plate equipped with new syringes would be hard to perform for an automatic machine. That is to say, this would require a very accurate positioning of the holes above the locking pins that must be pressed in, and an accurate insertion of the pipette tip into the interior space that is subdivided by inner walls. This could not be managed by conventional automatic machines. Thus, it is a disadvantage of such a box that the pipette tips hit the grid-like subdivision when being inserted, and fall out of the plate.
Starting from this, the present invention is based on the objective to provide a carrier for pipette tips which is particularly suited for the utilisation in automatic machines. That is to say, the carrier is distinguished by its particular stability and its suitability for being handled by automatic elements (like gripping arms, metering head e.g.). Thus, an essential aspect of the objective is to provide a carrier whose plate and frame cannot be separated without intent, by errors of the automatic machine e.g., but whose elements (plate and frame) can be detached simply when this is intended.